Thermic siphon



JUN@ y W3- G. J. CHRISTENSON 'yf-)43,46

THERMIC S PHON 3 Sheets-Sheet l led July 8, 1935 5 I I I .Q A v \\w .N.k

Jun@ M3@ G. J. cHRlsTNsoN THERMIC S IPHON Filed July 8, 1935 3Sheets-Sheet 2 June 9, 1936. G. J. cHRlsTEN'soN THERMIC SIPHON FiledJuly 8, 1.955 5 Sheets-sheet 5 Patented June 9, 1936 UNITED 515.6311515IPn'rENT oFFleE THERMIC SIPHON -Gust J. Christensen, Chicago,Ill.,'assignor to Locomotive Firebox Company, Chicago, Ill., acorporation of Delaware y I Application July 8, 1935, Serial No. 30,288

'5' claims. (o1. 12a- 68) This invention relates to improvements inthermic siphons and it consists of the matters hereinafter described andmore particularly pointed out in the appended claims.

One oi' the objects of the present invention is to provide a thermicSiphon for use in connection with a flrebox of the combustion chambertype and which siphon is so formed as to have such flexibility aswill'prevent fractures developing from expansion and contractioncaused.l by wide temperature changes.

, A further object of the inventionris to provide a multi-compartmentsiphon for use inra rebox of the combustion chamber type and wherein apart of one compartment is disposed inthe combustion chamber and has aninlet neck that opens through one o-f the sheets thereof and the othercompartment has an inlet neck that opens prei- Aerably through the frontthroat sheet, the last mentioned neck though relatively straight,Y beingof such length as to provide adequate ilexibility. Another object of theinvention is to provide a multi-compartment therrnic Siphon including aninlet neck for each compartment, the longer neck being made integralwith the body and communicating with the rear endV thereof and at thesame time being transversely staybolted so as to resist the highinternal pressure generated therein.

The above mentioned objects of the invention as well as others, togetherwith the manyY advantages thereof, will more fully appear as I proceedwith my specification.

In the drawings: Y

Fig. l is a longitudinal Vvertical sectional view through a relativelyshort' combustion chamber type of locomotive firebox embodying the-preferred formof the invention.

Fig. 2v is'V a transverse vertical sectional'view through a part'of therebox as taken on the line 2--2 of Fig. 1l y Fig. 3 is a longitudinalvertical sectional view through a relatively long combustion chambertype of locomotive firebox embodying a vmodified. form of the invention.

Fig.` 4 is a detail vertical sectional viewv on an enlarged scale,through one of the inlet necks for the siphon shown in Fig. 3,the planeof the section being indicated by the line 4-4 of Fig. 3.

Referring now in detail to that embodiment of the invention illustratedin Figs. land 2 of the accompanying drawings,` the rebox therein shown,which is of the comparatively shallow, combustion chamber type, includesthe crown sheet 5 which merges into the inner side sheets 6, the innerback lsheet 'I and inner throat sheet 8. The crown sheet extendsvforwardly of the inner throat sheet 8 to form the top of the combustionchamber 9. VThis chamber is closed at the front end by a flue sheet II)and the bottom II of said' chamber joins the front end of the innerthroat' sheet 8.

The outer back sheet is indicated at I2; the outer side sheets areindicated at I3 and the outer throat sheet is indicated at I4. Saidsheets cooperate with the top sheet and outer side sheets I3 in formingthe back Water leg I5, the side Water legs I6 and the iront throat I'Irespectively, all in communication with the water'space Ill-of theboiler.

The back and side water legs and the Afront throat are bottomed by a mud'ring I9 andportions, of the inner and outer back sheets are formed toVcoact in providing a fuel door opening 20.

-Each siphon as herein shown comprises a flat hollow 4body formed toprovide front and rear,

relatively deep compartments or chambers 22-23 respectively, separatedby an intermediate compartment'24 of less depth; The body includeslaterally spaced side walls 25-25 and transversely rounded front andrearV end walls 25 and 21 respectively. Said side Vand end walls areflared outwardly around the entire top end of the body,

into a laterally extending flange 28a. This iiange is fitted and weldedas at 29 in a suitable longitudinal opening in thev crown sheet. Thusthe Y open top end of the Siphon body provides a common discharge forall three compartments of theV siphon body, into the water space of theboiler abo-ve the crown sheet.

The front wall 26 oi the body is disposed at a relatively steep angleextending downwardly and rearwardly from the crown sheet and providesbut a relatively small'amount of overhang for this end Vof the body. Therear wall 21 oi the body is also disposed at a relatively steep angle,substantially opposite that vof the frontwall and extends downwardly andforwardly to merge into a rounded corner or nose 21o. That part of thevby means of inside curved corners 28 to merge Y body defining the rearcompartment 23 terminates in a stub-like tubular extension 3|.

Associated with said rear compartment of the siphon body is a downwardlyand forwardly extending inlet neck 32 of substantial length. As shownherein, said neck is made from a piece of seamless tubing and the frontend of said neck is anchored in a ilexible diaphragm 33 preferablyflanged up from the top portion of the inner front throat sheet 8. Therear end of said neck is butt welded to the end of the body extension 3|above mentioned, as indicated at 34.

The bottom portion 35 of the front compartment 22 which is transverselyrounded, is disposed above and arranged at a lesser inclination thanthat of the neck 32. This bottom portion along with the parts of theside and front end walls of the siphon body are formed to provide astub-like tubular extension 36 for the front compartment of the body.Said extension or neck receives one end of an inlet tube 31 whichextends downwardly and is curved slightly outward to be secured in asuitable diaphragm-like opening in the bottom of the combustion chamberso as to open into the water space of the boiler at this point. Theinlet tube 31 is also preferably made of seamless tubing of a diametersubstantially the same as that of the neck 32. When two siphons are usedin a firebox, the inlet tubes for the front compartments of both siphonsopen through the bottom of the combustion chamber at points spaced, oneon each side of the median line of said combustion chamber bottom.

The bottom of the intermediate compartment 24 is formed by the topportion or part of a substantially circular formation 38. Anotherportion of said formation merges into a rounded rear corner 39 for thefront compartment and said corner blends into the rounded bottom 35 ofsaid compartment. A third portion of said substantially circularformation forms the front end for the rear compartment and merges intothe top of the stub-like tubular extension 3|..

Preferably the entire siphon body and the tubular extensions 3|-36therefor, are made from an integral sheet, cut to such shape that whenfolded upon itself by means of asuitable form block, produces the bodyand extensions shown. Such an integral structure will have a line ofweld extending the length of the front wall, along the bottom of thefront compartment, around the substantially circular formation 38 anddown along the top of extension 3|. Also, a line of welding will followdown along the rear wall 2l to merge into the corner 21a, said line ofwelding being necessitated because of the removal of certain excessmetal from the sheet, that permits the making of the inclined rear wallof the body without a puckering or buckling at said corner. To brace thebody of the siphon against internal pressures, the same is transverselystaybolted as at 4D. Due to the outline shape of the body, lessstaybolts are required than in a conventional siphon body and thiswithout sacrificing the safety factor.

Instead of making the entire body and the main inlet neck from a singlesheet of metal, that part of the body comprising the front compartmentmay be made from a single sheet of metal and that part of the bodycomprising the rear compartment and the main inlet neck extension may bemade from a single sheet of metal and the two parts joined by buttwelding at about the middle of the intermediate compartment 24.

While a two part body requires more welding operations, it has certainadvantages in the economy in plate material, due to the use of smallersheets and to the manner in which the grain of the metal in the twosheets thus used, may be disposed. Whichever way the siphon isfabricated, that is, either from one or two sheets of metal, theoperation of the siphon is the same and the advantages gained over theconventional siphons are likewise the same.

In either instance, the arrangement of the parts is such that therelatively long neck is under compression when in a cold condition aswhen there is no re in the rebox. Such compression, of course, is inrelation to the body of the siphon and substantially equals the amountof the movement due to expansion, as when the firebox is being firedunder service conditions. Under such conditions, when the siphon isunder service heat and pressure, only slight stresses, incapable ofstarting fracture at the inside corners previously mentioned are presentbecause the force of the expansion will return the neck and the upperpart of the siphon to their normal positions and thus neutralize themovement thereof.

In Fig. 3 of the drawings, I have illustrated the invention as embodiedin a rebox longer than that shown in Fig. 1 and having a combustionchamber 9a Aof greater length. To adapt the siphon to the increasedlength of iirebox and combustion chamber, the length of the siphon body2|a is increased accordingly. Preferably, this increase in length of thesiphon body is made up in the front end chamber 22a so that a goodlyportion of said front end chamber is disposed entirely within saidcombustion chamber. With such a front end structure, the front wall 26ais arranged at a greater inclination than in the structure shown in Fig.1.

While the length of the front compartment is thus increased, the lengthof the rear compartment 23a preferably remains the same as before andits position or spacing with respect to the inside back sheet 'laremains the same as before. Thus the distance between the tubularextension 3|a, and the inside throat sheet 8a becomes greaterto'necessitate an inlet 32a of greater length.

By reason of the use of an inlet neck of greater length, greaterflexibility in the neck is inherent. Therefore, in such a constructionit may be preferable to staybolt the intake neck. Furthermore, if theneck is stay bolted it is not necessary that it be of seamless tubing.The conventional practice of making the neck integral with the body maybe followed when the device is so formed. Under such conditions the bodyof the siphon may be made from one or more metal sheets of the properoutline shape folded to form the body and the neck 32a. 'I'he neck 32awill then be 0f a circular cross section having a line of butt welding32h along its top as best shown in Fig. 4. Such a welded neck ispreferably staybolted as at 32e` to reinforce the same against internalpressures. Under ordinary practice, a staybolted neck may have morerigidity, but due to the length of the neck herein described, therequisite flexibility desired is still present. In all other respects,the siphon includes the same structure as that described in connectionwith Figs. 1 and 2.

When the use of an arch is desired in the fire-l box, arch tubes 4| maybe employed in connection with the necks 32 or 32a and which arch tubesare arranged parallel with and in the inclined planes of said necks.Such an arch may consist of bricks 42 all of the same pattern shape attheir side edges. This avoids the expense of using bricks of differentpattern shapes at said edges. The bricks thus used will have a bettersupporting engagement upon the necks and arch tubes than is afforded bythe bulge on the conventional siphon.

By reason of the construction described, it is apparent that because ofthe siphon having a greater length, the same increases the superficialarea and consequently the heating surface of the siphon. This induces agreater water evaporating and steaming action and fore and aft watercirculating action in the boiler so that quiescent areas aresubstantially eliminated and sediment accumulation prevented. Again,such a structure avoids the necessity of using a separate Siphon in thecombustion chamber and this of course, reduces manufacturing andinstallation costs.

While in describing the invention, I have referred in detail to theform, 'arrangement and construction of the various parts thereof, thesame is to be considered only in the illustrative sense so that I do notwish to be limited thereto except as may be specifically set forth inthe appended claims.

I claim as my invention:

1. In a locomotive boiler iirebox having a combustion chamber, a hollowwater steaming and circulating wall including a body, a tubular inletneck for said wall communicating at one end with the front bottom partof the body and opening at the other end through a part of thecombustion chamber into the adjacent water space of the boiler, a secondtubular inlet neck com-municating at one end with the rear bottom partof the body and opening at the other end into water space of the boilerrearwardly of the combustion chamber, said body having a single outletopening through the crown sheet of the firebo-x for the discharge ofwater supplied to the body by said inlet necks.

2. In a locomotive boiler rebox having a combustion chamber, a hollowwater steaming and circulating wall, the top oi which presents anelongated opening in the crown sheet of the firebox with the iront endof the said wall projecting into the combustion chamber, an inlet neckfor the said front end of said wall and opening through a rebox sheetforming a part of the combustion chamber and a second inlet neck for therear end of said water wall opening through a rebox sheet at a pointrearwardly of the combustion chamber.

3. In a locomotive boiler firebox having a combustion chamber, a hollowwater steaming and circulating wall, the top of which presents anelongated opening in the crown sheet of the rebox with the front end ofthe said wall proiecting into the combustion chamber, an inlet neck forthe said front end of said wall and opening through a iirebox sheetforming a part of the combustion chamber, and a second inlet neck forthe rear end of said water wall opening through a rebox sheet at a pointto the rear of the combustion chamber, the second mentioned inlet beingstraight and having a length greater than the first mentioned one whichis curved.

4. In a locomotive boiler rebox, ,a hollow water steaming andcirculating wall including a body presenting an elongated opening in thecrown sheet of the firebox and comprising spaced, 9

staybolted sides butt welded at their meeting edges, each side includingan integral semi-circular neck extension, butt welded at their meetingedges to form an inlet neck for said body communicating at one end withthe water space oi the boiler below the bottom of the iiues therein andcommunicating at the other end with the bottom of the body at a pointrearward of its front end, said neck being transversely staybolted.

5. AV thermic Siphon including a flat hollow body, a relatively longstraight, downwardly extending inlet neck for the Vrear end of said bodyand a relatively short curved, downwardly extending inlet neck for thefront end of the body.

GUST J CHRISTENSON.

